Lithuanian (lĭthˌōāˈnēən) [key], a language belonging to the Baltic subfamily of the Indo-European family of languages (see Baltic languages). The official language of Lithuania since 1918, Lithuanian is spoken by approximately 3 million people there and by an additional half-million elsewhere in the world, chiefly in the Western Hemisphere. The importance of Lithuanian in linguistic studies stems from its designation as the most ancient of the living Indo-European languages. It is also the language closest to Proto–Indo-European, the ancestral tongue from which all the Indo-European languages evolved. Currently, Lithuanian uses a modified Roman alphabet for writing.
See L. Dambriunas et al., Introduction to Modern Lithuanian (1980).